A031241 a(n)=least k such that base 5 representation of n begins at s(k), where s=A031235.

1, 2, 3, 4, 14, 6, 1, 10, 12, 24, 9, 18, 2, 22, 34, 11, 21, 30, 3, 4, 13, 23, 33, 42, 119, 48, 14, 89, 104, 47, 6, 7, 67, 70, 50, 8, 17, 1, 110, 53, 10, 27, 98, 113, 56, 12, 37, 101, 116, 194, 51, 126, 24, 179, 88, 66, 16, 9, 85, 125, 81, 18, 19